Aerodrome or flying-machine.



PATENTED JUNE so, 1908.

B. R; MUMFORD.

AERODROME 0R. FLYING MACHINE.

APPLICATION FILED JULY 11,1906.

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E. R. MUMFORD. AERODROME 0R FLYING MACHINE.

APPLICATION TILED JULY 11,1906.

2 BHEET8SHBET 2 UNITED STATES PATENT OFFICE.

EDWIN RICHARD MUMFORD, 0F DUMBARTON, SCOTLAND.

annonnome on FLYING-MACHINE.

Specification of Letters Patent. Application filed Jul 11, 1906. Serial No. 325,711.

Patented June 30, 1908 -type described in my patent application Serial No. 300,752. In the a paratus therein described a comparatively llirge number of propellers of more or less specific pitch and areas and driven at a specifically proportionate speed are used for both sus enslon and propulsion and are so arranged .t at their inratus is capable o variation.

The present invention has for its object to retain the advanta es of this form of apparatus while simpliying and reducing. the weight, and to provide more effectively against certain contingencies.

According to my present invention the axes of the propellers are fixed relativel to .clination relativel to the body of the appathe plane of what may be termed the hu of the apparatus and are either at right angles thereto or are inclined (their degree of inclination being fixed) as "may be found most convenient under particular conditions and their inclination to the vertical .to the degree requisite to bring about the conditions hereinbefore referred to is brought about by the inclination in the direction of its length of the whole apparatus. This inclinationis brought about by a rudder (or rudders) acting in a horizontal plane. The action of the rudder may be assisted by the longitudinal movin of a weight (say t e operators). s

i In carrying out my Invention, the hull of the aerodrome is, a light framework, of bam-' boo, aluminium, or other suitable material, provided rneans for ca g the motor or motors drivlng the prope ers and for accommodatin the operators. Horizontal ad justahle rud ers, consisting of light but rigid frames upon which is laced suitable textile material, may be arranged upon horizontal axes at one end or at both ends of the hull framework. There ma be one of these horizontal rudders preferabl there may be one at each end, and the are so poaitioned'and formed as to offer litt e rey at the after end or sistance to the downward flow of air from the propellers. In operation, these rudders, or that rudder when there is but one, are so inclined from the horizontal in the direction of the length of the apparatus that the reaction (due to the horizontal movement of the apparatus) of the air on them (or on it) is suchas to incline the whole ap aratus to an extent to give the inclination the ropeller axes requisite'to give the desirerl more or less horizontal direction of flight to the apparatus. I In addition tothis function the horizontal rudder (or rudders) and plane surfaces (if there be such) serve to balance the a paratus and to afiord a certain de eeof ad tional'safety should the prope 'ng machinery break down.

A rudder (or rudders) upon a vertical axis is also provided under control of the operator for steering in a horizontal plane 1f there be but one it is preferabl at the 1' end of the apparatus. Prefera l however,

om the vertical to I use a known form of rudder capable of.

causing bodil inclination and to some extent also bodillvs lateral movement of the apparatus anda 0 simultaneously ofsteermg It in a horizontal plane. This form of rudder, consists of a framework of triangular,

truncated triangular (that is to say, trape zoidal) rectangular, or other convenient form, carried at its apex (or corresponding oint when it is of form other than trianguar).1ipon an axis in the fra ,of the apparatus and at one end of it. T e framework may be made to a certain extent flexible or preferably and more conveniently the pint of its connection to theap'paratus maybe a ball-and-socket, Hookes or other universal joint, but in any case such thatthe member.at the baselfit being assumed for convenience in descri tion that the frammg 1s triangular), is capa le of angular movement relatively to the apex and of lateral or vertical movement or conjoint lateral or vertical movement about the apex as a fixed point and it is covered with textile fabr1c secured to it by lacing. Means under control of the operator are provided for turning the framing about its axis; that 1s ;-turn1ng 1t relatively to the plane of the whole apparatus; or for inclining it ('i. e. mo 11; vertically about the 'oint) or for movmg 1t laterally the means prelerably being such that the various movements ma be made either conjointly or separately as may be dwired.

When the framing is moved vertically,

that is, if its outer part be raised or de ressed longitudinal plane it has a further and more effective steering effect in the horizontal lane as its outboard unbalanced weight then tends to tilt the apparatus as a whole to the side to which it is inclined. It is clear that guidance in a horizontal plane and ver; tically may be accomplished simultaneously by these conjoint movements of this form of rudder.

The combined suspensory and pro ulsive screw ropellers are arranged above t e hull upon s afts which are either of a fixed degree of inclination to the lane of the latter or which are vertical. here are at least two equal propellers, or there may be any convenient multiple of two, one half of their number being right-handed and the other half left-handed so as to eliminateany horizontal turningcouple, or the propellers may be otherwise proportioned and arranged to. this end. The propeller shafts are driven through suitable gearing from a motor or motors operated by any suitable power (for example, combustible vapor or gas) and referably arrangedbelow the propellers so that the whole wei ht of hull, motors, and operators is below t e suspensory propellers, '11. e. the point of suspension of the apparatus when it is in the air.

In order to increase the stability of the apparatus when in flight the axes of the propellers may be so mclined to one another that when produced they ass through a point either above or beneat the apparatus and so that the lines of reaction of the va rious propellers are not parallel to one another.

In operation, whether the 'ap aratus merely rise vertically, rise vertica y and move horizontally coincidently-i. e. proceed in-a plane inclined to the horizontalor move horizontally, is entirely dependent upon the angle in the direction of horizontal movement to the horizontal plane which the axes of the propellers are constrained to as-' sume by the lengthwise inclination of the apparatus as a whole, and this lengthwise inclination is brought about by the reaction of the air upon the horizontal rudders. Consequently, the a paratus is directed in flight in any direction y manipulating the rudder de- The propeller shafts may be so positioned that the paths of the propeller blades overlap, the propellers being so geared together,

2, being, respectively, a plan, a side elevation and an end elevation all diagrammatic at they do not foul one another of an example of the im roved aerodrome' rovided with six propel ers arranged at a ed inclination to the hull or framing of the app aratus-like parts being indicated through out by like reference letters.

Since the general construction of the pro pellers and framing is substantially similar to that described in my said earlier patent specification, hereinbefore referred to, it is unnecessary to enter minutely into the structure of the apparatus.

The six pro ellers, A, are carried upon shafts, B, whidh, as will be seen clearly in Fig. 2, are inclined to the vertical in a longitudinal direction, that is to say, they are inclined and not'at right an les to the-general plane of the framing or hu C. The shafts,

are driven from longitudinal shafts, D, by bevel gearing and the shafts, D, are in their turn driven from two petrol motors, E, by pitch chains. The motors, E, (which rotate reversely) are as will be seen in Fig. 3, interconnected by two pitch chains, Reach gearing witha sprocket wheel upon their respective driving shaft and with a sprocket wheel upon shafts, R, carrying upon them s ur wheels, S, gearing with one another.

he speeds of the two motors and of the whole gearing and propellers are thus absolutely synchronized as is obviously necessary in view of the arrangement of the last in the present example, and, at the same time, one motor is able to carry on the drive of all proellers at areduced speed should the other Break down. The 'motors, E, are carried upon a slat framing or latform, G, which also serves as a platform or the operators. In this example a single rudder, H, of triangular framing to drums or other devlces for operatin them conveniently situated uppn the .plat orm, G. The lower lines,'K pass over pulleys carroed on brackets, O, to the section attached by a ball oint at its apex to a 1g laterallythat either 40 tudin as a whole they may be arran operating devices. The operating devices are such that one of each pair of lines, J ,K,

and L, M, is aid out at the same speed as the other is hau ed in so that the airs of lines 5 are always taut and so hold their side of the rudder rigidly in all positions. Further, the device is such that either pair may be erated separately or both together. It is ur ther necessaryin order to incline the rudder air of lines may be aid out conjointly, w lile the other pair is eing hauled in. Such a device may very well consist of a number of drums upon which the various lines are wound and is ob- 5 viously besides being capable of wide; variation capable of being ap lied, by anyone skilled in the art, it is there ore not more particularly described.

In order that the length and width of the apparatus and consequently its'weight may be assmall as ossib e with a given ropeller dlamcter, t e propeller shafts, are placed at such a distance a art both longitudinally and transversely t rat the paths of the propeller blades, A, overlap the propellers being so eared together and the posi tions of their lades being so adjusted that they do not foul one another in rotating. This is clearly seen in Fig. 1, adj acent ropellers-which, of course, have only two b ades each other in a longitudinal direction-are so inclined transversely u on opposite sides of the apparatus and as s own 1n Fig. 3, that the axes of transversely opposite pairs meet, when roduced, in points beneath the longia i center line of the apparatus. the lines of reaction of the two sets? of propellers upon either side are not arallel with each other. To the same end, t e axes may be so inclined as to meet in points above the apparatus.

t is not necessary ,when the apparatus is designed for fli ht in contradistinction to' more ascension that the axes of the propellers should also be inclined -towards each other 5'0 longitudinally but where the apparatus is designed for ascension only they ma be thus inclined; that is to say, the axes of a thep'ropellers may pass when produced through a point either above or beneath the a paratus.

- Instead of inclining the propel er shafts longitudinally to the-plane of the apparatus ed at rightanglesthereto, the inclination of the apparatus as a whole: either by the movement of Weights,- or of its rudder, or rudders, having the same effect as if the apparatus be maintained'horizontal and the propeller shafts be inclined. I

It is to be understood thatthe numbers,

pitch, areas, and speed of the propellers are Thus to be devised in accordance with the general directions contained in the specification of my earlier atent hereinbefore referred to. The factorsm this direction are obviously; to a certain extent-interdependent; but it may be stated broadly that, for pro ellers of given diameter the efficiency of tirust per power depends mainly upon the ratio of pitch to diameter, and upon the ratioof surface blades to the total area of disk traversed by the bladesboth these factors should be within certain limits. For similar propellers, the efficiency of thrust for a given power increases with increase of diameter.

It has been found by actual test that flight can be accomplished with a certain minimum of ratio of total disk area of ropellers to the total wei ht to be lifted, wfiich ratio depends upon the designed degree of light ness and strength of the ropellers, and upon the power er weight of en ine ,or engines. It has also lieen found that fora given suitable design there is a higher limit of ratio of total disk area to total weight, beyond which the gain in efficiency of thrust per power,.due to increase of total disk area, is not sufficient to compensate for the extra weight due to increasing the total disk area. In machines of suitable light and strong construction, the limits of ratio of total disk area to total wei ht and power may be relatively far apart, and in such cases the margin of liftin force (and therefore acceleration of upwarc movement) is at its maximum midway between the limits. In machines of heavier'design the limits are narrowed, and the margin of lifting force is relatively reduced. And it is obvious that if the design be too heavy flight will be impossible for any ratio of disk area to r feet (t e total disk areathat is, the area covered by the blades when revolving-bein in all about 2950 square feet, while the totad -flat-areai. e.'the area of one side of the bladesis in all about.1,000 square feet, this' area rojected on the plane of revolution bein a out 750 square feet). These six prope ers are driven at about 40 revolutions per minute by motors (or a motor) Wei hing in all about 250 lbs. and developing a out 30 H. P. Thus it will be seen that for each pound of total load raised, the disk area of provided per pound of load is fit'h H. P. This for ascension, for horizontal flight much less power is necessary. y

What I claim is 1. The combination in an aerodrome having a plurality of propellers acting both for suspension and propulsion, shafts carrying said propellers arranged in pairs upon opposite sides of the apparatus, said opposite shafts being inclined downwardly, backwardly and towards each other so that if produced their axes would meet'in a longitudinal line beneath the apparatus.

2. The combination in an aeroclrome having a plurality of propellers acting both for sus ension and propulsion, shafts carrying sai propellers arranged in pairs upon opposite sides of the apparatus said op osite name to this specification, in the presence of two subscribing Witnesses.

EDWIN RICHARD MUMFORD.

Witnesses:

DAVID FERGUSON, WILFRED HUNT. 

